This is the finest cast sash pulley made anywhere! The Harwick pulley is sand cast in architectural bronze (SAE 40/C83600/CDA836), and features a removeable stepped bushing to provide for custom finishing. The pulley wheel rotates around a precision sealed ball-bearing. 1/4" threaded stainless shaft. Tested by an independent test lab for tensile strength above 7000 pounds! Working load 1300 lbs. Also available in Architectural Brass or custom alloys/finishes by special order.